Current hair transplantation techniques essentially rob Peter to pay Paul, redistributing hair, usually from the back of the head, to the balding area. However, according to Angela M. Christiano, PhD, from Columbia University Medical Center (CUMC), about 90 percent of women with hair loss are not strong candidates for hair transplantation surgery because of insufficient donor hair. A new technique developed by Dr Christiano and colleagues that generates new human hair growth from a patient's own cells could make transplantation feasible for such women, as well as men in the early stages of baldness.

The team, which included researchers from CUMC and Durham University in the UK, knew that rodent hair is easily transplantable, unlike human dermal papilla cells, which revert to basic skin cells when put into a conventional, two-dimensional tissue culture. They suspected that this is because rodent dermal papilla cells, which play a pivotal role in hair formation and growth, tend to form clumps in tissue culture that allows the papillae to interact and release signals that reprogram the skin to grow new follicles.

"This suggested that if we cultured human papillae in such a way as to encourage them to aggregate the way rodent cells do spontaneously, it could create the conditions needed to induce hair growth in human skin," says CUMC's Claire A. Higgins, PhD, who was first author of the study.

To put their suspicions to the test, the team harvested dermal papillae cells from seven human donors and cloned them in tissue culture. After a few days the team then transplanted the cultured papillae between the dermis and epidermis of human skin that had been grafted onto the backs of mice. New hair growth that lasted at least six weeks was seen in five of the seven tests, with DNA analysis confirming that the new hair follicles genetically matched the human donors.

"This approach has the potential to transform the medical treatment of hair loss," says Dr. Christiano. "Current hair-loss medications tend to slow the loss of hair follicles or potentially stimulate the growth of existing hairs, but they do not create new hair follicles. Neither do conventional hair transplants, which relocate a set number of hairs from the back of the scalp to the front. Our method, in contrast, has the potential to actually grow new follicles using a patient’s own cells. This could greatly expand the utility of hair restoration surgery to women and to younger patients – now it is largely restricted to the treatment of male-pattern baldness in patients with stable disease."

Before the technique can be tested in humans, Durham University's Colin Jahoda, PhD, who was co-study leader, says more work needs to be done into "the origins of the critical intrinsic properties of the newly induced hairs, such as their hair cycle kinetics, color, angle, positioning, and texture." But the team is hopeful that clinical trials could begin in the near future. "We also think that this study is an important step toward the goal of creating a replacement skin that contains hair follicles for use with, for example, burn patients," adds Dr Jahoda.

Researchers have created new human hairs using dermal papilla cells found inside the base of human hair follicles (Photo: Claire Higgins/Christiano Lab at Columbia University Medical Center)

Spheres of cultured papillae cells from human hair follicles successfully produced new human hair when transplanted between the dermis and epidermis of human skin (Photo: Claire Higgins/Christiano Lab at Columbia University Medical Center)